Extremely thin and defect-free Si-on-insulator fabrication by tunnel epitaxy

A novel technique for extremely thin and defect-free Si-on-insulator (SOI) fabrication, called tunnel epitaxy, is demonstrated. A lateral/vertical growth ratio of 20 is achieved with precisely controlled SOI film thickness, where the minimum thickness for the fabricated SOI is 0.05 μm. No defect was observed in the fabricated SOI with 〈001〉 lateral growth direction. The growth front is a flat (001) plane. The lateral growth length is limited to 1–2 μm by tunnel clogging, due to poly-Si grain growth. The tunnel epitaxy, however, has a potential for larger area SOI fabrication, because the fabricated tunnel length is 10 μm.